Here's some quick and dirty testing I did. I wouldn't take any of the individual results as perfect, but the comparisons should be solid. In the end, I'm really happy with the 4th setup. Swapped handle and attachment for a MicroMo cozy (fits perfectly), swapped lid to a 32oz QT drink lid, and I bent the base of the legs on the stove until the top of the stove sat nearly flush with the bottom of the Petrel.
Test | Fuel Start | Fuel End | Fuel Used (g) | Time (s) | Wt (g) |
1st test - totally original | 636 | 630 | 6 | 137 | 166 |
2nd test - swapped to cozy | 630 | 625 | 5 | 129 | 176 |
3rd test - swapped to QT lid | 625 | 619 | 6 | 143 | 153 |
4th test - bent legs of BRS to be closer to bottom | 619 | 613 | 6 | 134 | 153 |
5th test - no lid | 613 | 606 | 7 | 165 | 147 |
I ended up getting a 5g lid from the convenience store that fits slightly snugly over the cozy so that it doesn't come up while boiling. I just wish it was transparent instead of black, so I'm going to look for one of those.
I've got a bear hunt coming up in a couple of weeks. After that, I'm going to order another one and start monkeying around with the bottom of the shroud to see if it could both increase efficiency (by not touching the fins) and act as a partial wind screen.